Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
Teacher Notes and Answers
Chapter 10
SECTION 1
3. a. Liquid molecules are very mobile. This
mobility allows a liquid to take the shape of
its container. In liquids, molecules are in
contact with adjacent molecules, allowing
intermolecular forces to have a greater effect
than they do in gases. The molecules in
a liquid will therefore not necessarily spread
out to fill a container’s entire volume.
b. Polar molecules are attracted to adjacent
molecules and are therefore less able to
escape from the liquid’s surface than are
nonpolar molecules.
4. An attractive force pulls adjacent parts of a
liquid’s surface together, thus decreasing
surface area to the smallest possible size. A
sphere offers the minimum surface area
for a given volume of liquid.
5. Freezing is a physical change. The substance
solidifying is changing its state, which is
a physical change. It is still the same
substance so it has not changed chemically.
6. Evaporation is a physical change because it
involves a change of physical state. There
is no change in the chemical makeup of the
substance, which would be necessary for
a chemical change.
7. Evaporation is a form of vaporization. It
occurs only in nonboiling liquids when some
liquid particles enter the gas state.
Vaporization is a more general term that
refers to either a liquid or a solid changing
to a gas.
SHORT ANSWER
1. a. ideal gas
b. ideal gas
c. real gas
2. a. The energy is transferred between them.
b. Those with the lower molecule mass.
3. a. Gas molecules are in constant, rapid,
random motion.
b. As a gas is heated, each molecule’s
speed increases; therefore, the molecules
pass through the small hole more frequently.
4. a. b, d, c, a
b. All gases at the same temperature have
the same average kinetic energy. Therefore,
heavier molecules have slower average
speeds. Thus, the gases are ranked from
heaviest to lightest in molar mass.
5. Polar molecules attract neighboring polar
molecules and often move out of their
straight-line paths because of these
attractions.
6. c.
7. In both cases the average speed of the
molecules is proportional to temperature.
The distribution of molecules becomes
broader as the temperature increases. This
means that there are a greater number of
molecules traveling within a greater range
of higher speeds as the temperature
increases.
SECTION 3
SECTION 2
SHORT ANSWER
1. b
c
a
d
2. some possible answers:
ionic solid: MgO, CaO, KI, CuSO4
covalent network solid: graphite, silicon
carbide covalent molecular solid: dry ice
SHORT ANSWER
1. a
2. a. Intermolecular forces are between
separate molecules; intramolecular forces
are within individual molecules.
b. intermolecular
c. intramolecular
d. intermolecular
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
3.
4.
5.
6.
(CO2), sulfur, iodine metallic solid: any
metal from the far left side of the periodic
table
Solid lead is denser than the liquid form.
a. crystalline solid
b. crystalline solid
c. amorphous solid
d. amorphous solid
a. Metals have many electrons that are not
bound to any one atom; therefore they are
able to move throughout the crystal. In
covalent network solids, all atoms (and
electrons) are strongly bound in place and
are not free to move.
b. Solids have definite volume because
their particles are packed very close
together.
There is very little empty space into which
the particles can be compressed.
Even at high temperatures their particles are
held in relatively fixed positions.
c. In amorphous solids, particles are
arranged randomly; no specific amount of
kinetic energy is needed to overcome the
attractive forces holding the particles
together. Thus, they do not have a point at
which they melt, but melt over a range of
temperatures.
d. Ionic crystals have strong binding forces
between the positive and negative ions in
the crystal structure. Covalent molecular
crystals have weaker bonds between the
molecules.
The attractive forces between CH4
molecules are weak (dispersion forces).
Little energy is needed to separate the
molecules. Melting water ice involves the
breaking of many hydrogen bonds between
molecules, which requires more energy.
d
b
a
4. a. A
b. C
c. it decreases
d. ice and liquid water will vaporize,
forming water vapor
5. a. decrease
b. reverse reaction
c. forward reaction
6. a. about 75C
b. about 85C
c. about 38 kPa
d. Based solely on molar mass, CCl4 would
be expected to be less volatile than water.
However, CCl4 is nonpolar and thus has
weak intermolecular forces of attraction.
Water is polar and contains strong hydrogen
bonds between molecules. Thus, water is
less volatile despite its smaller molar mass.
SECTION 5
SHORT ANSWER
1. a. physical
b. chemical
c. chemical
d. physical
2. a. water
b. formaldehyde
c. water
d. water
3. Hydrogen bonding in water occurs between
a hydrogen atom of one water molecule and
the unshared pair of electrons of an oxygen
atom of an adjacent water molecule. It is a
particularly strong type of dipole-dipole
force. Hydrogen bonding causes the boiling
point of water and its molar enthalpy of
vaporization to be relatively high. The
water’s high surface tension is also a result
of hydrogen bonding.
4. a. 68.6 kJ/mol
b. 79.8 cal/g
5. a. 14.7 g
b. 0.814 mol
c. 4.89 kJ
SECTION 4
SHORT ANSWER
1. a
2. b
c
a
d
3. c
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
SECTION 1
SHORT ANSWER Answer the following questions in the space provided.
1. Identify whether the descriptions below describe an ideal gas or a real gas.
__________________ a. The gas will not condense because the molecules
do not attract each other.
__________________ b. Collisions between molecules are perfectly elastic.
__________________ c. Gas particles passing close to one another exert an
attraction on each other.
1
2. The formula for kinetic energy is KE  mv 2 .
2
a. As long as temperature is constant, what happens to the kinetic energy of the
colliding particles during an elastic collision?
_____________________________________________________________
b. If two gases have the same temperature and share the same energy but have
different molecular masses, which molecules will have the greater speed?
_____________________________________________________________
3. Use the kinetic-molecular theory to explain each of the following phenomena:
a. A strong-smelling gas released from a container in the middle of a room is
soon detected in all areas of that room.
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b. As a gas is heated, its rate of effusion through a small hole increases if all
other factors remain constant.
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_____________________________________________________________
4. a. ________________ List the following gases in order of rate of effusion,
from lowest to highest. (Assume all gases are at the
same temperature and pressure.)
(a) He
(b) Xe
(c) HCl
(d) Cl2
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
SECTION 1 continued
b. Explain why you put the gases in the order above. Refer to the kineticmolecular theory to support your explanation.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
5. Explain why polar gas molecules experience larger deviations from ideal
behavior than nonpolar molecules when all other factors (mass, temperature,
etc) are held constant.
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_______________________________________________________________
_______________________________________________________________
6. _____ The two gases in the figure below are simultaneously injected into
opposite ends of the tube. The ends are then sealed. They should just begin to
mix closest to which labeled point?
7. Explain the difference in the speed-distribution curves of a gas at the two
temperatures shown in the figure below.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
SECTION 2
SHORT ANSWER Answer the following questions in the space provided.
1. _____ Liquids possess all the following properties except
(a) relatively low density.
(c) relative incompressibility.
(b) the ability to diffuse.
(d) the ability to change to a gas.
2. a. Chemists distinguish between intermolecular and intramolecular forces.
Explain the difference between these two types of forces.
_______________________________________________________________
_______________________________________________________________
Classify each of the following as intramolecular or intermolecular:
__________________ b. hydrogen bonding in liquid water
__________________ c. the OH covalent bond in methanol, CH3OH
__________________ d. the bonds that cause gaseous Cl2 to become a liquid
when cooled
3. Explain the following properties of liquids by describing what is occurring at
the molecular level.
a. A liquid takes the shape of its container but does not expand to fill its
volume.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
b. Polar liquids are slower to evaporate than nonpolar liquids.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
SECTION 2 continued
4. Explain briefly why liquids tend to form spherical droplets, decreasing surface
area to the smallest size possible.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
5. Is freezing a chemical change or a physical change? Briefly explain your
answer.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
6. Is evaporation a chemical or physical change? Briefly explain your answer.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
7. What is the relationship between vaporization and evaporation?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
SECTION 3
SHORT ANSWER Answer the following questions in the space provided.
1. Match description on the right to the correct crystal type on the left.
______ ionic crystal
(a) has mobile electrons in the crystal
______ covalent molecular crystal
(b) is hard, brittle, and nonconducting
______ metallic crystal
(c) typically has the lowest melting
point of the four crystal types
______ covalent network crystal
(d) has strong covalent bonds between
neighboring atoms
2. For each of the four types of solids, give a specific example other than one
listed in the text.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
3. A chunk of solid lead is dropped into a pool of molten lead. The chunk sinks
to the bottom of the pool. What does this tell you about the density of the solid
lead compared with the density of the molten lead?
_______________________________________________________________
4. Answer amorphous solid or crystalline solid to the following questions:
__________________ a. Which is less compressible?
__________________ b. Which has a more clearly defined shape?
__________________ c. Which is sometimes described as a supercooled
liquid?
__________________ d. Which has a less clearly defined melting point?
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
SECTION 3 continued
5. Explain the following properties of solids by describing what is occurring at
the atomic level.
a. Metallic solids conduct electricity well, but covalent network solids do not.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
b. The volume of a solid changes only slightly with a change in temperature or
pressure.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
c. Amorphous solids do not have a definite melting point.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
d. Ionic crystals are much more brittle than covalent molecular crystals.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
6. Experiments show that it takes 6.0 kJ of energy to melt 1 mol of water ice at
its melting point but only about 1.1 kJ to melt 1 mol of methane, CH4, at its
melting point. Explain in terms of intermolecular forces why it takes so much
less energy to melt the methane.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
SECTION 4
SHORT ANSWER Answer the following questions in the space provided.
1. _____ When a substance in a closed system undergoes a phase change and the
system reaches equilibrium,
(a) the two opposing changes occur at equal rates.
(b) there are no more phase changes.
(c) one phase change predominates.
(d) the amount of substance in the two phases changes.
2. Match the following definitions on the right with the words on the left.
______ Equilibrium
(a) melting
______ volatile
(b) opposing changes occurring at equal
rates in a closed system
(c) readily evaporated
______ fusion
______ deposition
(d) a change directly from a gas to a solid
3. Match the process on the right with the change of state on the left.
______ solid to gas
(a) melting
______ liquid to gas
(b) condensation
______ gas to liquid
(c) sublimation
______ solid to liquid
(d) vaporization
4. Refer to the phase diagram for water in Figure 16 on page 347 of the text to
answer the following questions:
__________________ a. What point represents the conditions under which
all three phases can coexist?
__________________ b. What point represents a temperature above which
only the vapor phase exists?
__________________ c. Based on the diagram, as the pressure on the water
system increases, what happens to the melting
point of ice?
d. What happens when water is at point A on the curve and the temperature
increases while the pressure is held constant?
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
SECTION 4 continued
5. Use this general equilibrium equation to answer the following questions:
reactants 
 products  energy
__________________ a. If the forward reaction is favored, will the
concentration of reactants increase, decrease, or
stay the same?
__________________ b. If extra product is introduced, which reaction will
be favored?
__________________ c. If the temperature of the system decreases, which
reaction will be favored?
6.Refer to the graph below to answer the following questions:
__________________ a. What is the normal boiling point of CCl4?
__________________ b. What would be the boiling point of water if the air
pressure over the liquid were reduced to 60 kPa?
__________________ c. What must the air pressure over CCl4 be for it to
boil at 50C?
d. Although water has a lower molar mass than CCl4, it has a lower vapor
pressure when measured at the same temperature. What makes water vapor
less volatile than CCl4?
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
CHAPTER 10 REVIEW
States of Matter
SECTION 5
SHORT ANSWER Answer the following questions in the space provided.
1. Indicate whether each of the following is a physical or chemical property of
water.
__________________ a. The density of ice is less than the density of liquid
water.
__________________ b. A water molecule contains one atom of oxygen and
two atoms of hydrogen.
__________________ c. There are strong hydrogen bonds between water
molecules.
__________________ d. Ice consists of water molecules in a hexagonal
arrangement.
2. Compare a polar water molecule with a less-polar molecule, such as
formaldehyde, CH2O. Both are liquids at room temperature and 1 atm
pressure.
__________________ a. Which liquid should have the higher boiling point?
__________________ b. Which liquid is more volatile?
__________________ c. Which liquid has a higher surface tension?
__________________ d. In which liquid is NaCl, an ionic crystal, likely to
be more soluble?
3. Describe hydrogen bonding as it occurs in water in terms of the location of the
bond, the particles involved, the strength of the bond, and the effects this type
of bonding has on physical properties.
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
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Modern Chemistry
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States of Matter
Name: ______________________________Class: _________________ Date: _________________
SECTION 5 continued
PROBLEMS Write the answer on the line to the left. Show all your work in the
space provided.
4. The molar enthalpy of vaporization of water is 40.79 kJ/mol, and the molar
enthalpy of fusion of ice is 6.009 kJ/mol. The molar mass of water is 18.02
g/mol.
__________________ a. How much energy is absorbed when 30.3 g of
liquid water boils?
__________________ b. An energy unit often encountered is the calorie
(4.18 J = 1 calorie). Determine the molar enthalpy
of fusion of ice in calories per gram.
5. A typical ice cube has a volume of about 16.0 cm3 . Calculate the amount of
energy needed to melt the ice cube. (Density of ice at 0.C = 0.917 g/mL;
molar enthalpy of fusion of ice = 6.009 kJ/mol; molar mass of H2O = 18.02
g/mol.)
__________________ a. Determine the mass of the ice cube.
__________________ b. Determine the number of moles of H2O present in
the sample.
__________________ c. Determine the number of kilojoules of energy
needed to melt the ice cube.
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Modern Chemistry
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